How to find the unknown length of right triangle

Julie was able to walk 16 km through the zoo in 6 hours. how long will it take her to walk 24 km through the zoo?

Aremote-controlled boat can travel at 4 feet per second in calm water. the boat traveled 48 feet with the current, and then it traveled 16 feet against the current in the same amount of time. how fast is the current?

Yvaries directly as x. y =90 when x=6. find y when x=13